I used to take FG readings using a plastic wine thief, but since I use the wine thief for my barrel aged sours I don’t dare. Currently, I just guess-timate when the beer is done. Fortunately , over the past couple years I’ve acquaint myself with the behaviour of the same 5 yeast strains, and keeping with the same brewing and fermentation methods I’ve had luck estimating when the beer has reached FG. However, I’m curious to hear what approach my fellow brewers take with FG readings and fermenting in glass carboys?
You might have to shake it up and down a couple times to get enough of a sample for your hydrometer test tube. I’ve had mine for 11 yrs.
The only time I didn’t check gravity before racking, it turned out I had a stuck fermentation. I checked before kegging and discovered it…
Thanks Maxieboy, I never thought of that…11yrs. that’s exceptional. I’ve owned 3 siphons in the past 5 years and unfortunately, they’ve all cracked and ended up breaking. I switched over to the stainless steel racking crane. I even tried taking samples using the ss-racking crane and was not able to …
Lucky you weren’t bottling.
You might be thinking of an Auto Siphon. The pic above is a thief. It has a type of one way valve on the end to trap your sample when you lift it out. Depending on the level of the beer in the carboy(low), you can shake it up and down a little to force more beer in it.
Sanitized turkey baster.
Keeping separate plastics is probably good insurance when brewing sours. Why not just get a second wine thief? They’re what, maybe $8?
Maxiboy, it looks just like an auto siphon. My mistake. Good idea.
Denny, turkey baster. Humm, not a bad idea.
a10t2, i thought of buying a second plastic wine thief, but was just wondering what everyone else uses.
Siphon, by mouth :o
This is my SOP.
I use a long 10ML glass pipet with a pipet bulb then a few drops on the refractometer, then I run the numbers through the morebeer refractometer spreadsheet found at http://morebeer.com/public/beer/refractbeer.xls It’s more complicated than it needs to be but it’s fast, easier to clean a little bulb/pipet and I like gadgets ;D Also, there is no plastic to scratch or cloud up.
The turkey baster is a killer idea. I’ve seen stainless steel models at Bed Bath and Beyond.
Good idea. Bad spreadsheet. ;D
Killer spreadsheet! Love it! I just kegged a Kolsch on Sunday, morebeer spreadsheet reported FG at 1.004 and this new spreadsheet reports 1.007 - 1.008. This is closer to taste perception when I sampled the Kolsch.
I just catch (as opposed to ‘take’) a sample as I’m racking to the keg. I’ve only had a couple stalled ferments and in each case they weren’t going anywhere in the carboy. They had done all they were going to do and rousing, yeast energizer, etc weren’t doing anything anyway. So I just get it off the old yeast and if it is stuck I either pitch dry yeast or put it on a cake from a ‘good’ fermentation. Either way, it needed to get out of the carboy so racking was the next step regardless of whether it was stuck or not. So I don’t measure first, I just rack it and measure the caught sample. If I were bottling it’d be different.
I pull out my stopper with thermowell and let a drop or two fall on my refractometer… instant reading.
I also found the standard corrections to be off… over time I’ve settled on a rough linear correction of just adding 0.4 brix and using that reading in the ProMash calculator. This adds anywhere from 0.002 to 0.004 points to the FG, which always read low for me using the refractometer estimate. a10t2’s graph looks like he’s getting the same results in a more scientific way 
Yes, I switched to Sean’s spreadsheet too, it’s much better than the others.
I still owe you data Sean, but I haven’t had time to do any testing. 15 days until my defense. 
i purchase SS turkey(type) baster
very good, and safe !!
Good luck…hope you beat the rap! ;)
;D Thanks
That’s an acceptable excuse… for now.
Good luck!